The Russians marked the original barrels 1-5 depending on the headspace. This distance was measured from the back of the headspace gage to the barrel shoulder that seats against the trunnion. All of our barrels have been turned as #1's which is the shortest allowable distance. This will give the builder plenty of room should they need to adjust the depth by facing off material from the shoulder to thread deeper into the trunnion. The barrels DO NOT have the handguard retainer cuts nor the extractor clearance cuts. These will need to be done after setting the headspace.